In addition to the thixotropic liquids, viscous liquids form an important group among the liquids with non-Newtonian behavior, which require special measures and means for their handling. This also applies to the design of metering containers.
The invention relates to a metering container for viscous liquids having an opening in a container space for the viscous liquids and means for closing the container opening.
A metering container has been disclosed in, for example, DE-C-1 206 141 for the application of glue. Two closing means are provided for closing the container, namely a slide for separating the container space from the applicator roller and two slides which can be moved toward one another in the manner of a gate, overlap the applicator roller and are intended to prevent drying out.
On the one hand, the inner slide which closes the container space presented a problem since it had to be operated from the outside, which made sealing difficult, especially since one section of the slide was always outside the container and one section inside, and there was always displacement between these parts during opening and closing. During these movements, the adhering glue was conveyed to the outside and could drip freely there, so that the work was not clean.
On the other hand, operation of the two outer slides with the aid of a cord pull against the force of a spring was not only rather complicated in design and susceptible to faults, but it did not prevent drying out during long periods of standing, which--owing to the large number of parts--then led to complicated cleaning work.
For non-adhesive substances, various metering containers have been proposed, for example in US-E-28 120. However, these are sector-like slots which extend parallel to the circumference of the rotary slide and on the one hand permit only a limited application width and on the other hand could not completely prevent thread formation when tacky substances were used, since both slots are located on the same radius and there would be a thread-cutting shearing effect only when their edges curved with respect to a chord plane relative to their curvature result in nonuniform glue application so that for this reason alone they are unsuitable for this purpose.
FR-A-1 197 509 adopted another approach to the solution of the problem. There, a metering roller acting on the actual applicator roller itself defines two metering gaps on its two sides in that this metering roller is arranged exactly in the bottom opening of the container and projects partly into the container space and partly outside. To close the two gaps remaining at its two sides, a thin spindle is inserted in each case between the metering roller and the concave container bottom and is intended to cover the gap.
A precondition of this solution is that the two spindles are produced very precisely in order to avoid leaving a cavity, and that the glue (or another viscous liquid) contains no lumps or impurities which could become lodged between the spindles and the container wall and thus prevent the sealing effect of the two spindles. In addition, during operation the metering roller continuously rubs against one of the spindles, which therefore impairs the functioning and the rotation of this roller, while the spindle on the other side of the metering roller is constantly raised from its sealing position as a result of its rotation, after which a return to the sealing position within the viscous medium is not ensured by anything.
However, if leaks occur in the known embodiments, the viscous liquid flows out in thin threads which are deposited everywhere and are difficult to remove. It is therefore the object of the invention to provide a metering container of the type stated at the outset so that it is easy to seal, does not carry viscous liquid, such as glue, together with surface sections pushed outside, and that the seal holds it securely in its closed position without there being any danger of contaminating thread formation.